1. Technical Field
This invention relates generally to pistons for internal combustion engines, and more particularly to pistons having lubrication features within a pin bore of the piston.
2. Related Art
It is know to provide a piston for use in an internal combustion engine with lubrication features with axial spaced and aligned pin bores of the piston. Typically, the lubrication features comprise grooves extending about the circumference of the pin bores between opposite sides of the pin bores. Oil ports typically extend from a source of oil supply, such as an oil gallery of the piston, into the associated groove. Although these constructions generally provide suitable lubrication to the pin bores to reduce friction between the pin bores and a wrist pin extending through the pin bores, they reduce the available bearing area of the pin bores, and thus, the loads are increased between the pin bores and the wrist pin. This is of particular concern in applications wherein the loads are relatively high, such as in high performance, high horsepower engine applications. In addition, the manufacture of the piston is complicated by requiring precise machining to intersect the grooves with the oil ports.
It is also known to incorporate lubrication features comprising scallops extending axially across the full width of the pin bores. The scallops have oil ports, that deliver oil thereto via an oil supply, such as from a gallery of the piston. The scallops act to distribute oil in the pin bosses, while also serving as oil reservoirs for oil to provide constant lubrication within the pin bores.